Intangible Assets Including Goodwill - Intangible Assets by Class (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2021	Dec. 31, 2020
Intangible asset balances by major asset class
Gross Carrying Amount	$ 18,952	$ 18,874
Accumulated Amortization	(5,417)	(5,079)
Net Carrying Amount	13,535	13,796
Amount of foreign currency translation increase (decrease)	(137)	279
Capitalized software
Intangible asset balances by major asset class
Gross Carrying Amount	1,854	1,777
Accumulated Amortization	(837)	(814)
Net Carrying Amount	1,017	963
Client relationships
Intangible asset balances by major asset class
Gross Carrying Amount	8,874	8,838
Accumulated Amortization	(2,275)	(2,056)
Net Carrying Amount	6,599	6,783
Completed technology
Intangible asset balances by major asset class
Gross Carrying Amount	5,972	5,957
Accumulated Amortization	(1,784)	(1,671)
Net Carrying Amount	4,188	4,286
Patents/trademarks
Intangible asset balances by major asset class
Gross Carrying Amount	2,196	2,246
Accumulated Amortization	(480)	(499)
Net Carrying Amount	1,717	1,747
Other intangible assets
Intangible asset balances by major asset class
Gross Carrying Amount	56	56
Accumulated Amortization	(41)	(39)
Net Carrying Amount	$ 14	$ 16